1. Field of the Invention
The invention relates to a cigarette smoking device of the type comprising a smoking cylinder with an inlet and outlet valve, means including a smoke separator for connecting a cigarette to be smoked to an inlet side of the cylinder, a piston in the smoking cylinder, an electric motor and a post-connected transmission for imparting reciprocating movement to the piston and an electrical control system for generating a variable feed voltage for the electric motor.
2. Description of the Prior Art
The smoking-down of cigarettes for analytical and mensuration purposes in described in particular in DIN specificaton No. 10240. Devices of the kind referred to in the foregoing, so-called automatic smoking machines, are utilised for the smoking-down operation. The piston in the smoking cylinder of the smoking machine performs a working cycle for each puff taken at the cigarette which is to be smoked down. The draw or puff period, i.e. the duration of the suction stage of the working cycle, and the draw or puff volume, i.e. the dimension of the suction stroke, should be adjustable. Furthermore, a particular puff pattern or cycle should be followed during each puff.
In a known device of the kind referred to in the foregoing, the piston of the smoking clinder is actuated by a uniformly operating d.c. motor via a crank gear. This establishes a sinusoidal puff or suction pattern. The variation of the suction period is performed by analogous variation of the rotational speed of the d.c. motor. A variation of the suction volume is possible only by a mechanical shift of the eccentric of the crank gear. The momentary setting has to be verified by means of test runs during which the suction volume is rechecked. The suction pattern is invariably fixed.
In another known smoking device, the piston is moved in the smoking cylinder by means of a uniformly operating d.c. motor via a rack and pinion gear. This establishes a rectangular suction pattern. The adjustment of the suction period occurs as before by means of speed change of the d.c. motor, the adjustment of the suction volume occurring by means of a mechanical variation of the terminal position of the piston. In this case too, the adjustment of the suction volume has to be verified on test runs and the suction pattern is invariably fixed as a structural parameter.
In the case of the known devices, it is consequently impossible to operate with different suction patterns or cycles in one device. Any change in the suction period affects the suction volume and vice-versa, so that setting up modified values becomes very protracted.